Centrifugal casting appliance



L. W. AYERS CENTRIFUGAL CASTING APPLIANCE Aug. 16, 1927.

Filed Jah 1x Patented Aug. 16, 1927.

UNITED STATES PATENT OFFICE.

CENTRIFUGAL CASTING` APPLIANC.

Application led January 29, 1924. Serial No. 689,270.

This invention relates to `appliances for producing metal casts in whichgreat accuracy as to structural conformation is required; and an objectof the invention is to 6 provide a means for producing delicate caststhat are Substantially true to the conformation -of the mold.` j vTo'that end I provide an appliance' with a speed control that willdischarge the Ametal from its crucible into the mold by a centrifugalforce the intensity of which is predeter mined; and which force ismaintained at a uniform intensity until the metal cast has hardened andcooled; thereby preventing the cast from shrinking away from the moldWall as`it is cooled. In other words, I rotate the appliance at apredetermined and uniform speed so that the metal from the crucible willbe driven into the mold and .held there by centrifugal force until it isthoroughly cooled; and the uniform centrifugal force applied tothe metalwill tend to hold it in contact with the mold Wall While cooling so thatshrinkage away from the wall is 25 minimized. n

` Heretofore centrifugal 'appliances of this class have been devisedthat at the first moment of casting have been actuated at a high speedthat quickl loses its momentum and decreases in spee to a stop; andusually the stop occurs just at the critical time when the metal isstarting to cool and ofttimes in a position in which the cast willshrink away suiiiciently from the wall to make it undesirable and-illshaped; and an object of my invention is to provide a means formaintaining centrifugal force on the cast until it yhas thoroughlyhardened and cooled.

An object of the invention is to provide a centrifugal appliance thatcan be detachably connected to the shaft of a speed controlled motorsuch as are commonly used by dentists7 jewelers and tine metal workers;so that by regulating the motor speed the casting appliance can beoperated at a known and uniform speed. 1 i

Another object is to 'provide an appliance that is easily adj listed toa position for melting and discharging the limpression forming pigmentsuch as wax from the mold; and also adjusting it to a position forchargingv and heating the metal 1n the crucible,'which adjustments tothe two positions are accomplished by quarter rotations of the motorshaft. c

Another object of the invention is to provide a centrifugal castingappliance with an electrical heater connected thereto that is adapted tomelt the impression formingpigment such as wax from the mold; and to 6odry the mold and harden the composition of which the mold is formed, andalso to heat the mold so that the casting metal will more readily entertherein and contact with the wall thereof. Another object of theinvention is to provide an appliance that is easy to construct, assembleand operate; and which is also strong and durable in construction, andwhich can be made and sold cheaply.

Features of the invention are shown in the construction, combination andarrangement of the parts whereby an appliance that is easily adjusted,operated and of great utility is provided. 75

Other objects, advantages :ind features of invention may appear from theaccompanying drawing` the snbjoined detail description and the appendedclai1n The accompanying drawing illustrates the 8o invention.

Figure 1 is a side View of a motor with a centrifugal casting appliancethat is constructed in accordance with this'invention attached to themotor shaft, and showing the 85 appliance in a position to heat and drythe mold; and also showing a side plate removed from the motor casing todisclose one mem. ber of the motor speed control,l

Fig. 2 is a `right end vieivof the motor 90 shown in Fig. l, showing theappliance turned on the shaft to a position to receive the moldingmetal.

Fig. 3 is an enlarged fragmental section on line, Fi 1, showing theappliance' -turned on the s aft to the position shown in on line Fig. 3,with the a pliance turned on the shaft to the position s Aown in Fig. 1.Fig. is a central section through the mold casing showing a fusible inlaembedded in the'mold forming materialI with a bore formin pin attachedthereto.

Fig. 6 is a vlew analogous to Fig. 5, with the bore forming pindetached; and showing the fusible inlay melted out of the mold.

Fig. 7 is a cross section o n line w", Fig. 4. Fig. 8 is a cross sectionon line w8, Fig. 4. Figi 9 is a broken detached side View of thecentrifugal arm.

Fig. 10 is a perspective view of the housing and associated partsdetached from the centrifugal bar.

The centrifu al casting a pliance 1 com` rises a bar 2 t at is provi edwith anlorice 3 that is adapted to be fitted over and secured by a-screw4 to a shank 5 on a chuck 6, that is adapted to be connected to a shaft7 on -the motor 8. v f

The motor 8 is ofwell known construction preferably having a speedrange'of about 1000 to 3600 revolutions per minute with a control switch9 of usual construction for regulating the speed.

The speed control and operation of the motor are 'well known and aretherefore not shown and described in detail, except to state thatthespeed of the motor can be con-` f and the other end threaded for the nut15,

by which means the housing 14 is adjustably secured'to the end 10 of thebar 2. The housing 14 is provided with an integral annular s acing ring16 that extends inwardly towar .the axis of the housing 14; and th1sring1 forms a seat for an insuinto Ithe housing 14 and secured thereinby an inner cylindrical housing 18 that at one end is: threaded to t thethreaded end of the housin 14, and which has its other end ittin iluswithin'the inner surfaces of the ann ar ring 16. A

The heating coil 17 is adapted to be placed in circuit with a source ofelectricity, not shown, b means of the lead wires 17 and detachab e 19adapted tok be fitted to a lu socket in. the oss 20 extending from thehousing 14. A crucible casing 20 is shrunk in the inner housing 18; andthis casing is provided with :xv-cylindrical metal lining shell 21 whichat tted the eating; coil 17 that is fitted o ne end is provided with aninner annular ring 22 that forms a retainer for the noncombustible'material 23 of which the crucil' 1, 2 and 4, and engages the mold cyliner i A mold 28 is formed by embedding a'fbody 29 that fuses at a lowtemperature in investment 30 that is poured into the cylinder 26 aroundthe body that is supported on a pin 31 that when withdrawn from theinvestment 30 forms a small lead hole to the mold 28.

Preferably the body 29 is formed of wax and the pin 31 is set therein asshown in the drawing so that when the Casin 26 is seated. and secured inthe shell 21 and t e appliance turned to the positions shown in Figs. 1,4 the heating coll 17 can be ener 'zed to melt the wax in the mold 28 sot at both theV wax and pin 31 will fall by gravity to empty the mold andclear the lead hole thereto; and

the heater 17 can be continued in operation until the mold 28 and cementare dried and v hardened.

speed to drive the molten metal 32 by cen-` trifugal force into the mold28;. and the predetermined speed of the motorcan be uniforml maintaineduntil the metal has coole in the mold.

A ball' 33 is threaded'so it is adjusted on the threaded end 34 of thebar 2 so that a balance can be established ,between the ball and thecasting appliance at the other end of said bar.

In practice, the applianceis operated as stated to' heat the mold sothat the metal will more readily enter therein and contact to the moldwall,and byv centrifugal means the metal isforced and held against themold wall until both the metal and mold have cooled, thereby forming acast of su erior conformation.

claim: g

A centrifugal casting'appliance set forth comprising a bar having one ofits end portions flattened and the other end rounded and threaded, abalance ball threaded on said threaded end, said attened 'end having aslot formed therein, a. housing ad'ustably mounted in said slot; aninner ousin Within said housing and spaced therefrom;

Y electrical coils between said inner and outer housings, a detachableelectricalv connection to said coils, 9, Crucible said inner housing, alcrucible in one end ofsaid Crucible casing, a; mold cylinder removablymounted in said crucible casing, and means 10 to rotate said bar aroundan axis,

In testimony whereof, I -have hereunto set myhand at Los` Angeles,California, fhis'l23rd day of January, 1924.'

LOREN WILLIAM AYRS.

